Digital interval timer with interval end signal

ABSTRACT

A SYNCHRONOUS MOTOR OPERATES A RATCHET MECHANISM WHICH PERMITS A SPRING TO DRIVE AN INTERNAL DIAL IN A STEPWISE FASHION TO CAUSE THE INTERVAL TIME REMAINING TO APPEAR AS AN INTEGER IN REGISTRY WITH A VIEWING WINDOW. RATCHET TEETH ROTATABLE WITH THE INTERVAL DIAL ARE PERIODICALLY LIFTED TO MOVE AN EXTENSION OF ONE OF THE TEETH OUT OF ENGAGEMENT WITH STATIONARY RATCHET TEETH AND ALLOW THE INTERVAL DIAL TO SHIFT TO DISPLAY THE NEXT LOWER TIME INTEGER. A CAM FOLLOWER COOPERATES WITH A CAM ROTATABLE   WITH THE INTERVAL DIAL TO MAINTAIN THE DRIVING CONNECTION TO THE SYNCHRONOUS MOTOR DURING THE INTERVAL, TO DISENGAGE THE CONNECTION AT THE END OF THE INTERVAL, AND TO SHIFT A BUZZER ARM INTO OPERATIVE RELATION TO THE MAGNETIC FIELD OF THE MOTOR TO SIGNAL THE END OF THE INTERVAL. THE INTERVAL DIAL THEN IS MANUALLY ROTATED TO THE &#34;OFF&#34; POSITION AND THE BUZZER ARM CEASES TO OPERATE.

March 2, 1971 BAS'SETT 3,566,599 I DIGITAL INTERVAL TIMER WITH INTERVAL END SIGNAL Filed July 8. 1969 3' Sheets-Sheet 1 V t; ini Mgrch '2, 1971 BASSETT 7 3,566,599

DIGITAL INTERVAL TIMER WITH INTERVAL END SIGNAL Filed July 8, 1969 3 Sheets-Sheet 2 March 2 1971 R. M. BASSETT DIGITAL INTERVAL TIMER WITH INTERVAL END- SIGNAL 3 Sheets-Sheet S Filed July g. 1969 United States Patent US. Cl. 58-2114 15 Claims ABSTRACT OF THE DISCLOSURE A synchronous motor operates a ratchet mechanism which permits a spring to drive an interval dial in a stepwise fashion to cause the interval time remaining to appear as an integer in registry with a viewing window. Ratchet teeth rotatable with the interval dial are periodically lifted to move an extension of one of the teeth out of engagement with stationary ratchet teeth and allow the interval dial to shift to display the next lower time integer. A cam follower cooperates with a cam rotatable with the interval dial to maintain the driving connection to the synchronous motor during the interval, to disengage the connection at the end of the interval, and to shift a buzzer arm into operative relation to the magnetic field of the motor to signal the end of the interval. The interval dial then is manually rotated to the off position and the buzzer arm ceases to operate.

According to this invention there is provided an interval timer in which the time remaining in the interval appears as an integer, for example the whole number of minutes remaining, with the display indexing once each minute to the next lower integer. At the end of the interval a buzzer arm is released to give an audible signal. The mechanism is operated by a synchronous electric motor which is arranged to drive through suitable reduction gearing an hour hand, a minute hand, and a second hand. A gear is rotatable with the second hand and it drives an intermediate gear that is carried by a lever which permits the intermediate gear to engage or disengage the second hand gear. The lever is rotatable about the axis of a driven gear which is in constant mesh with the intermediate gear. A pinion is concentric and rotatable with the driven gear and drives a ratchet lift gear at a speed of about one revolution in 30 minutes. The ratchet lift gear is concentric with a set of stationary ratchet teeth uniformly spaced about a circle with one tooth omitted. Rotatable with the ratchet lift gear are four uniformly spaced ratchet lift teeth which are arranged to ratchet past teeth of a movable ratchet that is rotatable and endwise slidable with respect to the axis of the ratchet lift gear. A spring biases the movable ratchet translatorily toward the ratchet lift teeth and angularly away from the interval setting toward the off position. A radial extension of one of the movable ratchet teeth engages one of the stationary ratchet teeth to hold the movable ratchet in an interval indicating position. As the ratchet lift gear and the ratchet lift teeth rotate the latter ratchet past the movable ratchet teeth of the movable ratchet and move it against the biasing force of the spring until the radial extension of one of the movable ratchet teeth clears the stationary ratchet tooth engaged thereby. The spring then indexes 'ice the movable ratchet teeth one tooth whereupon the ratchet lift teeth engage the next sationary ratchet teeth and the radial extension of one of the movable ratchet teeth engages the next stationary ratchet tooth. A translucent dial plate is secured to and moves with the movable ratchet. It carries the series of whole minute numbers along its periphery only one of which is visible through a window in a face plate, each minute number being radially aligned with a movable ratchet tooth. A lamp behind the dial plate in registry with the window makes the minute number more readily visible. The dial plate is rotated manually to the desired minute number and thereby the spring is correspondingly tensioned to return the dial plate to the o position. Also movable with the movable ratchet is a cam having a relatively deep notch corresponding in position to the end of the time interval and a relatively shallow notch corresponding to a successive and o position of the movable ratchet and reflected by a corresponding indication on the dial plate. A cam follower is biased radially against the cam and constitutes an extension of the lever which carries the intermediate gear to shift it out of driving engagement with the second hand gear when in either of the notches. When the cam engages the relatively deep notch, the buzzer arm is released to vibrate in the magnetic field of the motor. On manual rotation of the movable ratchet to cause the cam follower to engage the relatively shallow notch, the buzzer arm is held against vibration.

In the drawings: FIG. 1 is a view, in front elevation of a digital interval timer in which this invention is embodied. FIG. 2 is a View, in rear elevation, of the timer shown in FIG. 1. FIG. 3 is a view, similar to FIG. 2, with the back plate having been omitted to show more clearly certain details of the underlying construction. FIG. 4 is a view, similar to FIG. 3, with the circular plate and cam omitted to show additional underlying details of construction. FIG. 5 is a sectional view at an enlarged scale taken generally along line 5-5 of FIG. 2. FIG. 5A is a portion of the horizontal sectional view, shown in FIG. 5, and illustrates the locked position of the long tooth of the movable ratchet teeth with respect to one of the stationary ratchet teeth. FIG. 6 is a view, in front elevation, of the interval dial and movable ratchet teeth. FIG. 7 is an elevational view showing the gear shifting lever in the position that it occupies at the end of the preset interval at which time the buzzer arm is released. FIG. 8 is a view, similar to FIG. 7 but showing the position of the gear shift lever in the off position. FIG. 9 is a perspective view of the buzzer arm. FIG. 10 is a plan view of the spring which biases the interval dial. FIG. 11 is a plan view of the ratchet lift teeth and ring. FIG. 12 is an elevational view of the ratchet lift teeth and ring shown in FIG. 11.

In FIG. 1 the reference character 10 designates, generally, a digital interval timer embodying this invention. The timer 10 includes a face plate 11 which may be formed of metal and on which are located hour markings 12 with respect to which an hour hand 13, a minute hand 14 and a second hand 15 are arranged to rotate. A time set knob 16 is provided to set the hour and minute hands 13 and 14 to the correct time. To one side of the hour markings 12 there is a window 17 in which appears an integer 18, such as the integer 20, indicating that this number of minutes remain of the preset interval which may range anywhere from 1 to 30 minutes. This range is illustrated and described as representing a typical range of minutes for a time interval. Other ranges can be employed. The integers 18 are imprinted on an interval dial 19 which is shown in more complete detail in FIG. 6. Below the window 17 is an interval set knob 20.

In FIG. 2 a motor support plate 22 is shown. It is suitably mounted in spaced relation from the rear side of the face plate 11. A synchronous motor, indicated generally at 23, is mounted on the motor support plate 22. The motor 23 can be constructed as disclosed in Svarnias US. Pat. No. 3,350,589, issued Oct. 31, 1967. As disclosed in this patent the motor 23 has an extension 24 of its magnetic field structure. It is arranged to cooperate with a hammer 25 of a buzzer arm, indicated generally at 26 and shown in more detail in FIG. 9, which is mounted on a pivot pin 27 and is biased by a coil spring 28. When the hammer 25 is moved into close proximity with the distal end of the extension 24, the buzzer arm 26 vibrates and provides an audible signal. The coil spring 28, FIG. 10, acts to bias the buzzer arm 26 in a clockwise direction as viewed in FIG. 2. An arm 29, FIGS. 7 and 8, extends from the buzzer arm 26 and is arranged to move between stop pins 30 and 31 which extend forwardly from the motor support plate 22 to limit its movement.

In order to move the buzzer arm 26 into and out of operative position, it is provided with a slot 34, FIG. 9, in which is located an offset buzzer control arm 35 which forms an extension of a lever that is indicated, generally at 36. The lever 36 is pivoted on a stub shaft 37, FIG. 5, which is rotatably mounted in a plate 38 that is mounted on and spaced from the rear side of the face plate 11. The manner will be described hereinafter in which the lever 36 pivots the buzzer arm 26 against the biasing action of the coil spring 28 to bring the hammer 25 into operative position with respect to the extension 24 of the magnetic field structure of the motor 23.

As shown in FIGS. 3, 4 and 5, a second hand gear 39 is arranged to be rotated, in conventional manner, by the synchronous motor 23 through a reduction gear train. The second hand gear 39 rotates conjointly with the second hand 15 which is located on the front side of the face plate 11. The second hand gear 39 is arranged to mesh with an intermediate gear 40 which is rotatably mounted at 41 on the lever 36. Except when the interval dial 19 is being rotated from a preset position to the off position, the lever 36 occupies the position shown in FIG. 8 in which the intermediate gear 40 is out of driving engagement with the second hand gear 39. Between the rear side of the face plate 11 and the front side of the plate 38 there is positioned a driven gear 42 which is in constant mesh with the intermediate gear 40 as indicated in FIG. 5. The driven gear '42 is secured to and rotates with the stub shaft 37. On the opposite side of the plate 38 a pinion 43 is secured to the stub shaft 37 and rotates therewith. The pinion -43 meshes witha ratchet lift gear 44 that is rotatably mounted on the rear side of the plate 38. For illustrative purposes it is pointed out that the arrangement is such that the ratchet lift gear 44 rotates at a speed of one revolution each 30 minutes.

In FIG. 4 the relation between the pinion 43 and ratchet lift gear 44 is shown more clearly. Here it will be observed that the ratchet lift gear 44 has four rectangular openings 47 through which four ratchet lift teeth 48 project. They are shown in more detail in FIGS. 11 and 12 where it will be observed that they extend from a ring 49. If desired, the ratchet lift teeth 48 can be formed integrally with the ratchet lift gear 44.

In FIG. it will be observed that the ratchet lift gear 44 and the ring 49 are rotatably mounted about a reduced diameter section 50 of a stationary ratchet tooth support 51 which is secured to the plate 38 by pins '52 as shown in FIG. 4. The ratchet tooth support 51 has stationary ratchet teeth 53 located along its periphery. They are uniformly positioned with one missing as indicated at '54. Attention is called to the fact that the stationary ratchet teeth 53 are located along a circle having a diameter, indicated at 55, which is less than the diameter, indicated at 56 FIG. 6, along which movable ratchet teeth 57 are located. The movable ratchet teeth 57 are carried by a circular plate 58 to which the interval dial 19 is secured by pins 59. The interval dial 19 is rotatably together with the ratchet teeth 57 and circular plate 58 which is secured to a shaft 60 that is journaled in a bearing 61 FIG. 5, carried by the plate 38 and ratchet tooth support 51. The shaft 60 not only is rotatable but also is endwise movable in the bearing 61 and it has the interval set knob 20 secured to its forward end;

As shown in FIG. 6, the movable ratchet teeth 57 include one long tooth 62 which is arranged to engage one of the stationary ratchet teeth 53 to effect operation of the interval dial 19 in a stepwise fashion. Attention is called to the fact that the ratchet lift teeth 48, FIG. 4 are located along a circle somewhat greater in diameter than the diameter indicated at 56 in FIG. 6 so that they bear against the movable ratchet teeth '57 and 6-2 for the purpose of moving the interval dial 19 and parts associated therewith rearwardly and away from the face plate 11 while maintaining parallelism between the interval dial 19 and the ratchet lift gear 44 to operate the interval dial 19 in the stepwise fashion.

As shown in FIG. 5, a coil compression spring 64 is provided for biasing the interval dial 19 forwardly and also is arranged to be wound by operation of the interval set knob 20 so that it is biased to rotate toward the ofl position. One end of the coil compression spring 64 is secured at 65 to the circular plate 58. The other end is secured at 66 to a back plate 67 which is shown more clearly in FIG. 2. -Also shown in FIG. 2 is a coil tension spring 68 which is connected to an arm 69 which extends from the lever 36 and an arm 70' which extends from the upper left corner of the back plate 67. The coil tension spring 68 acts to bias the lever 36 in a clockwise direction to hold the intermediate gear 40 out of engagement with the second hand gear 39.

In FIG. 8 it will be observed that a cam 73 is formed on the rear side of the circular plate '58. The cam 73 has a circular cam surface 74 with which a distal end 75 of a cam follower finger 76 fromthe lever 36 is arranged to engage. The spring 68 biases the distal end 75 of the finger 76 into engagement with the circular cam surface 74. A relatively deep notch 77 is provided along the circular cam surface 74 and adjacent it is a relatively shallow notch 78.

As shown in FIG. 7, when the distal end 75 of the finger 76 engages the relatively deep notch 77 under the influence of the coil tension spring 68, the buzzer arm 26 is pivoted to bring the hammer 25 of the buzzer arm 26 into proximity with the extension 24 of the magnetic tfield structure of the motor 23 against the biasing action of the coil spring 28. The movement is limited by the stop 31. In this position the buzzer arm 26 vibrates and continues to vibrate until the interval set knob 20 is rotated manually to bring the relatively shallow notch 78 into registry with the distal end 75 of thefinger 76 as shown in FIG. 8. This causes the lever 66 to rotate in a counterclockwise direction and to permit the buzzer arm 26 to shift to the inoperative position shown here where its movement under the action of the coil spring 28 is limited by the stop 30.

The interval dial 19 can be formed of metal. Also it can be formed of translucent plastic. When the interval dial 19 is formed of translucent plastic, the time marking integers 18 can be rendered more readily visible by light from a lamp 79 that is aligned with the window 17 and is mounted on a support bracket 80 that is formed integrally with the back plate 67 as shown in FIG. 2.

At the end of the preset interval after the interval set knob 20 rotates the cam 73 to shift the distal end 75 of the finger 76 from the relatively deep notch 77 to the relatively shallow notch 78, FIG. 8, the off indication appears in the window 17. When a time interval is to be set, the interval set knob is rotated to rotate the cam 73 in a counterclockwise direction indicated by arrow 81 in FIG. 8. The movable ratchet teeth 57 ratchet past the ratchet lift teeth 48 and the long tooth 62 ratchets past the stationary ratchet teeth 53 until the desired integer time marking 18 appears in the window 17, for example the integer 20. Such rotation of the cam 73 brings the distal end 75 of the finger 76 into engagement with the circular cam surface 74 and pivots the lever 36 in a counterclockwise direction to cause the intermediate gear 40 to engage the second hand gear 39 as shown in FIG. 4. The ratchet lift gear 34 then is rotated in the manner indicated with the ratchet lift teeth 48 engaging the respective movable ratchet teeth 58 to lift them gradually away from the stationary ratchet tooth support 51 until the long tooth 62 clears the respective stationary ratchet tooth 53. At this instant the spring tension applied to the coil compression spring 64 on the setting of the time interval by the rotation of the interval set knob 20 biases the interval dial 19 and parts rotatable therewith to the next position where the endwise biasing action of the spring 64 moves the interval dial 19 and the long tooth 62 into engagement with the next stationary tooth 53 and shifts the integer 18 appearing in the window 17 to the next integer. The stepwise rotation of the cam 73 continues in a clockwise direction, indicated by arrow 82 in FIG. 8, until the distal end 75 of the finger 76 enters the relatively deep notch 77. At this time, as previously described, the buzzer arm 26 is moved to the position shown in FIG. 7 and it continues to sound an audible alarm until the interval set knob 20 is rotated manually to rotate the cam 73 and bring the distal end 75 of the finger 76 into the relatively shallow notch 78.

Attention is directed to FIG. 5 which shows the position of the long tooth 62 with respect to one of the stationary ratchet teeth 53 at the instant that the movable ratchet teeth '57 have been elevated by the ratchet lift teeth 48 to the maximum extent. FIG. 5A shows the long tooth 62 in locked engagement with the next stationary ratchet tooth 53.

What is claimed as new is:

1. A digital interval timer comprising:

a ratchet lift gear rotatable about an axis, driving means for rotating said ratchet lift gear at a constant speed,

stationary ratchet teeth about said axis,

a digital interval dial rotatable about said axis,

ratchet teeth on said dial about said axis at least one of which is arranged to engage one of said stationary ratchet teeth,

means biasing said dial for rotation from a time interval set position toward a time interval end position and for translation toward said stationary ratchet teeth, and

ratchet lift tooth means on said ratchet lift gear for engaging said ratchet teeth on said dial and shifting them translatorily away from said stationary ratchet teeth and said one tooth out of engagement with one of said stationary ratchet teeth to permit said biasing means to rotate said dial to the next position and said one ratchet tooth into engagement with the next stationary ratchet tooth.

2. The digital interval timer according to claim 1 wherein means interrupt operation of said driving means at the end of the time interval.

3. The digital interval timer according to claim 2 wherein said means for interrupting operation of said driving means includes:

a cam rotatable with said dial, and

a cam follower engaging said cam.

4. The digital interval timer according to claim 3 wherein:

said cam follower constitutes an extension of a lever pivoted adjacent said ratchet lift gear,

a pinion is rotatable about the pivot axis of said lever and engages said ratchet lift gear,

a gear is rotatable with said pinion, and

an intermediate gear is carried by said lever, engages said gear rotatable with said pinion and is shiftable with said lever out of and into driving engagement with a constantly rotating drive gear forming a part of said driving means.

5. The digital interval timer according to claim 4 wherein said driving means includes a synchronous motor.

6. The digital interval timer according to claim 1 wherein audible signal means is operated at the end of the time interval.

7. The digital interval timer according to claim 6 wherein means interrupt operation of said driving means at the end of the time interval.

8. The digital interval timer according to claim 7 wherein said means for interrupting operation of said driving means includes:

a cam rotatable with said dial, and

a cam follower engaging said cam.

9. The digital interval timer according to claim 8 wherein:

said cam follower constitutes an extension of a lever pivoted adjacent said ratchet lift gear,

a pinion is rotatable about the pivot axis of said lever and engages said ratchet lift gear,

a gear is rotatable with said pinion, and

an intermediate gear is carried by said lever, engages said gear rotatable with said pinion and is shiftable with said lever out of and into driving engagement with a constantly rotating drive gear forming a part of said driving means.

10. The digital interval timer according to claim 9 wherein:

said audible signal means includes a buzzer arm, and

means on said lever cooperative with said buzzer arm to effect operation thereof when said intermediate gear is shifted out of driving engagement with said drive gear.

11. The digital interval timer according to claim 10 wherein said cam has a relatively deep notch along its surface engaged by said cam follower at the end of the time interval and a relatively shallow notch engaged by said cam follower on manual rotation of said cam to the off position of said dial to prevent further operation of said arm.

12. The digital interval timer according to claim 1 wherein:

said stationary ratchet teeth are located along a circle,

said ratchet teeth on said dial are located along a circle having a diameter greater than that of said circle along which said stationary ratchet teeth are located, and

one of said ratchet teeth on said dial extends radially to engage one of said stationary ratchet teeth.

13. The digital interval timer according to claim 12 wherein said ratchet lift tooth means includes a plurality of uniformly spaced ratchet teeth to move said dial translatorily while maintaining parallel relation between it and said ratchet lift gear.

14. The digital interval timer according to claim 13 wherein:

a cam is rotatable with said dial,

a cam follower engages said cam and constitutes an extension of a lever pivoted adjacent said ratchet lift gear,

a pinion is rotatable about the pivot axis of said lever and engages said ratchet lift gear,

a gear is rotatable with said pinion, and

an intermediate gear is carried by said lever, engages said gear rotatable with said pinion and is shiftable With said lever out of and into driving engagement References Cited with a constantly rotating drive gear forming a part UNITED STATES PATENTS of said driving means. 15. The digital interval timer according to claim 1 gig 522 when 5 2,886,910 5/1959 Koci 58-5 means provide a window through which only a single interval marking on said interval dial is visible, that RICHARD BwwlLKlNsoN, Primary Examiner portion of said interval dial carrying interval markings being formed of light transmitting material, and FRANKLIN Asslstant Exammer a light source illuminating the interval marking visible 10 U.S. Cl. X.R.

throu h said window. 5 85, 128 

